This study presents a multivariate behavioural genetic analysis of the relationship between education, intelligence and age of first birth. Analyses investigated the mediational role of education in explaining the relationship between intelligence and age of first birth at both the phenotypic and behavioural genetic level. The data come from the National Longitudinal Survey of Youth (NLSY), a nationally representative survey that included genetically informative full-and half-sibling pairs (n=1423 pairs). Respondents were aged 14 to 22 when contacted in 1979. Heritability estimates were 0·32, 0·50 and 0·06 for IQ, education and age of first birth, respectively. Shared environment estimates were 0·35, 0·23 and 0·20 respectively. Common genetic and shared environmental factors were substantial in explaining the relationship between intelligence and education, and also education and age of first birth. Education partially mediated the relationship between intelligence and age of first birth only in the phenotypic analyses. After considering the genetic and shared environmental factors that influence all three variables, evidence for mediation was less convincing. This pattern of results suggests that the apparent mediational role of education at the phenotypic level is in fact the result of underlying genetic and shared environmental influences that affect education, IQ and age of first birth in common.

Self-esteem, the affective or evaluative appraisal of one's self, is linked with adaptive personality functioning: high self-esteem is associated with psychological health benefits (e.g. subjective well-being, absence of depression and anxiety), effective coping with illness, and satisfactory social relationships. Although several pathways have been hypothesized to effect within-family transmission of self-esteem (e.g. parenting style, family relationship patterns), we focus in this article on genetic influences. Genetic studies on both global and domain-specific self-esteem and on both level and stability of selfesteem converge in showing that (i) genetic influences on self-esteem are substantial, (ii) shared environmental influences are minimal, and (iii) non-shared environmental influences explain the largest amount of variance in self-esteem. We advocate that understanding of current issues in self-esteem research will be enriched by including behavioural genetic approaches.

Sex steroid loss and replacement have effects on specific cognitive processes in older men. Furthermore, estrogen has the potential to reverse the neurotoxic effects on memory performance caused by androgen deprivation.

SummaryObjective To examine the association of cognitive function with sex steroid and sex hormone binding globulin (SHBG) levels among elderly men. Design Prospective cohort study, The Osteoporotic Fractures in Men Study (MrOS), consisting of 5995 US community dwelling men of 65 years or older. Patients One thousand six hundred and two men were chosen randomly from MrOS cohort for sex steroid level measurements by Mass Spectrometry (MS) at baseline. Two thousand six hundred and twenty-three MrOS participants with sex steroids measured using RIA were also examined. Measurements Baseline and follow-up (4AE5 years later) performance on two cognitive tests: Trails B (executive function and motor speed) and 3MS (global cognitive function). Baseline total testosterone and oestradiol were measured by MS. Free testosterone (free-T) and free oestradiol (free-E) were calculated. SHBG was measured by radioimmunoassay. Data were analysed using linear regression. Results Baseline free-T and free-E levels were not associated with cognitive performance or change in cognition, following adjustment for age, education, race, health status and alcohol use. Baseline SHBG levels were inversely associated with follow-up trails B (P = 0AE03) and 3MS performance (P = 0AE02). Higher SHBG was associated with an increased risk of cognitive decline. Total sex steroid levels were not associated with cognitive performance. Conclusions Despite large numbers of participants and rigorous sex steroid measurements, we did not observe an association between cognition and either testosterone or oestradiol levels. We conclude that endogenous sex steroids in the normal range are not related to executive function or global cognitive function in elderly men. High SHBG deserves further examination as a risk factor for cognitive decline.

Past research suggests that early pubertal maturation predicts delinquency for Anglo American boys. Little research has been done on the effects of pubertal maturation on problem behavior for boys of other ethnic groups. This study investigated the relationship between relative pubertal status and delinquency for Anglo American, African American, and Mexican American adolescent boys. Early-maturing boys across all three ethnic groups reported higher levels of both violent and nonviolent delinquentbehavior. These results are consistent with a theory of differential peer access and not consistent with a theory of asynchronicity between testosterone-driven aggression and social-cognitive maturity.